Not all buildings that appear impressive in a city skyline are as polished on the inside. Cities around the world contain abandoned or unfinished skyscrapers due to financial crises that forced the end of construction, civil war fighting that turned the buildings into battlegrounds, or reasons that remain a mystery.

Here are 10 abandoned skyscrapers around the world and how they got to be that way.

Ryugyong Hotel — Pyongyang, North Korea

Ryugyong Hotel.
Ho New/Reuters

The abandoned Ryugyong Hotel in Pyongyang is also known as the " Hotel of Doom" due to the mysterious nature of its construction and its ominous, empty presence in the middle of North Korea's biggest city.

Work on the 105-story building began in 1987 under the rule of Kim Il Sung, Kim Jong Un's grandfather. The project ceased in 1993 because of an economic depression after the collapse of the Soviet Union. It appears to have stopped and started a few times since then based on satellite images of nearby construction equipment and new walkways, but if and when the hotel will open is still unclear.

Built as a spa, the 14-story structure had 450 guest rooms, attracting legendary guests such as Lyndon Johnson, Judy Garland, the Three Stooges, and even American criminals Bonnie and Clyde. Although it continued to thrive throughout the Great Depression, it closed in 1972 due to flagging business.

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The Drew (formerly Fontainebleau) Las Vegas — Las Vegas, Nevada

The Fontainebleau Las Vegas hotel was 70% complete when the Great Recession hit and construction stopped in 2009. Since then, the 63-story hotel has sat unfinished and abandoned on the Las Vegas strip for nearly 10 years.

Plaza Tower — New Orleans, Louisiana

The 45-story Plaza Tower was built in the 1960s as an office building. But the 7,000-square-foot floors proved too small for many tenants, and illnesses reportedly caused by mold and asbestos forced it to close in 2002, according to The Times-Picayune. It was bought by a developer in 2016, but remains empty.

Book Tower — Detroit, Michigan

Book Tower opened in 1926. At 38 stories high, the skyscraper looms over the Detroit skyline. After financial troubles hit the city in the 1970s, the building was added to the National Register of Historic Places in 1982, and has been abandoned since the last tenant left in 2009.

"The Book Tower is a major missing piece of Detroit's architectural fabric," Amy Elliott Bragg, president of the board at Preservation Detroit, told the Press. "It's so big, it's so tall, it's been an empty, looming building in Detroit's skyline for so long. So this is huge news for Detroit and preservation."

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Insignia Tower — Mexico City, Mexico

Insignia Tower, or Torre Insignia, was built in 1962 to house the National Bank of Public Works in Mexico City, according to CDMX. After the Mexico City earthquake in 1985, the 25-story skyscraper was abandoned. It was sold to an American real estate company 10 years ago and is currently undergoing renovations.